Pump



NOV 11, 1930. G. D'. sUNDsTRAND 1,781,416

PUMP

Filed March 22. 192e z sheets-sheet 1 39 6,11 sfzszww @M ma@ Nov. 11, 1930.

G. D. SUNDSTRAND PUMP 2 sheets-'sheet 2 Filed March 22, 1928 atented Nov. 11, 1930 l STATS OFFICE.

GUSTAF DAV'ID SUNDSTRAND, OF BOCKFOBD, ILLINOIS, ASSIGNOR TO SUNDSTRAND CHINE TOOL C0., OF ROCKFOBD, ILLINOIS, A. CORPORATION OF ILLINOIS rum' Application led March 22, 1928. Serial No. 263,656.

embodying means to supply fluid to ,the cylinders at a comparatively low pressure.

Another object is to provide a multiple cylinder positive displacement pump embodying novelmeans for varying the output of the pump.

A further object is to provide a new and p Y improved multiple cylinder positive displacement pump embodying 'levers for actuating the pistons, and having an adjustable connection therewith to permit of varying of the stroke of the pistons.

ln pursuance of the foregoing objects, I aim to provide a pump comprising a plurality of cylinders having pistons reciprocating therein, means to reciprocate said pistons adjustable to vary the stroke of the'pistons, a gear pump arranged to supply iuid to the cylinders at low pressure, and a valve device arranged to control the inlet of low ressure fluid and outlet of high pressure dui to and from the cylinders.

Further objects and advantages of the invention will become apparent as the description proceeds.

ln the drawings:

F ig. l is a verticalsection through the preferred form of the invention taken substantially along the line1-1 of Fig. 3.

Fig. 1a is a view of the valve member.

Figs. 1b to 1t inclusive are transverse sections along the lines b-b to f-f respectively of Fig. 1B.

Fig. 2 isa view of the left hand end of the pump shown in Fig. 1, with the mounting plate removed, the view being taken on the line 2-2 of Fig. 1.

Fig. 3 is a section along the line 3-3 of Fig. 1.

While my invention is susceptible of embodiment in many different forms, I have shown in the drawings and will herein des/cribe in detail one such embodiment, with the understanding that the present disclosure is to be considered as an exemplication of the principles of the invention and is not intended .to limit the invention to the embodimentv illustrated. The scope of the invention will be ointed out in the appended claims.

s illustrated herein, the invention in its exemplary form comprises a housing 1 having a side wall 2 somewhat irregular in shape (see Fig. 3) and end walls 3 and 4. The means for actuating the pump is shown in the form of a drive shaft 5 rotatably mounted in the upper portion of the housing by means of a air of ball bearings 6, 7, one end of the shaft extending through an aperture in the wall-3 for connection to a prime mover. Mounted on this shaft for rotation therewith are a plurality of angularly displaced eccentrics which, as described hereinafter, are arranged to actuate a plurality of pistons 9.

The pistons are preferably mounted in a unitary cylinder block 10 having bores 11, for receiving the pistons, and which is pivotally mounted on an axis beneath and extending parallel to the axis of the shaft 5. As illustrated herein, the cylinder block has bearing portions 12, 13 at itsopposite ends rotatably mounted in bearing .portions 14, 15 formed in the end walls of the housin -1.

The pistons 9 are preferably roun ed on their upper ends and arranged to be actuated by a plurality of arms or levers 16 which are herein shown as being independently fulcrumed at one end on a common shaft 17 which extends parallel to the shaft 5. The free ends of the levers are arranged to be actuated by the eccentrics 8 and are provided with rollers 18 which ride upon the eccentrics. As will be most readily apparent from Figs. 1 and 3, when the shaft 5 is rotated, the force arms of the levers, i. e. the portions of the levers between the fulcrums thereof and the connection. with the eccentrics, will be actuated successively by means of the eccentrics, the load arms of the levers in turn forcing the pistons downwardly. As disclosed may be varied by moving the cylinder block about its pivotal axis from the position shown in Fig. 3 to a position wherein the pistons would contact the arms along the axis of the shaft 17, and the stroke of the pistons corre spondin ly varied from the maximum as determine by the throw of the eccentrics to a minimum, (in this case zero) A`To permit of so varying the stroke of the pistons means is provided for rocking the cylinderblock 10 about its pivotal axis. Preferably a segmental gear 19 is secured to vone end of the cylinder block, which gear meshes with a pinion 19a mounted on one end of a control shaft 20. This shaft extends through a bore in the end wall 4 of the housing and also through a mounting plate 21, to receive a hand lever 22 (shown in part). By rotating the shaft 20 by means of the hand lever, the cylinder block 10 may be rocked on its pivotal axis and the output of the pump varied as hereinafter more fully described.

ln order to insure a definite amount of fluid entering each cylinder during each return stroke of the pistons, the invention contemplates means for supplying fluid to the cylinders under pressure, the pressure being sucient to force the pistons upwardly into constant engagement with the arms 16 on their return stroke as well as to retain the rollers 18 in constant contact with the eccentrics so as to obviate the necessity of using springs or a positive connection between the arms and the pistons. As illustrated herein,

. a gear pump comprising intermeshing gears 23, 24 is provided for supplying the fluid under pressure to the cylinders. These gears are positioned intermediate the outer surface of the housing wall 3 and a plate 25 which is spaced therefrom by means of a collar 26 and secured thereto by a plurality of bolts 27. The gear 23 is rotatably mounted on a pin 28 supported by the end wall 3 and is arranged to be driven by means of a gear 29 keyed to the drive shaft 5. The gear 24 is shown mounted on one end of a cylindrical valve member 30 which member is rotatably mounted in a valve sleeve 31. The sleeve is preferably positioned concentrically with the pivotal axis of the cylinder block 10 and in a bore 32 therein, andis secured against rotation by means of a pin 33'extending through menare the sleeve and an apertured plug 34 secured to the housing. l

The sleeve 31 is provided with a plurality of ports 35 therein, one for each cylinder, which ports are bpreferably ppsitioned adjacent the left hand walls of the cylinders as shown in Fig. 3,.'so that when the cylinder block is rocked in a counter-clockwise direction, the ports remain in 4communication with the cylinders. l

The valve member 30' is arranufed to control the inlet of low pressure iuidato. the cylinders during the intake strokes of lthe pistons and to control the .outlet of high presl sure fluid from the cylinders during the ex'- haust strokes of the pistons and is therefore provided with a longitudinal low pressure'in-"i take Vpassage 36 connecting with a plurality of low pressure intake ports 37 and has high pressure exhaust ports .38 which connect with an axially extending high pressure exhaust passage 39. This exhaust passage connects with a passage 40 in the plug 34 which serves as an outlet connection for the pump. lThe intake ports 37 and exhaust ports 38 are spaced about the periphery of the valve mem-- ber so that during continuous rotation of the Valve member during the operation of the pump, the ports are properly timed With the reciprocatlons of the pistons as determined by the. eccentrics, first to admit low pressure fluid to return the pistons and thereby completely ll the cylinders, then to out otf communication between the low pressure supply and the cylindersy and open the high pressure exhaust passages.

The inlet and outletto the pump are preferably provided at opposite ends of the housing. Thus as illustrated herein the inlet is provided adjacent the gear pump by means of a port 41 in the' end plate 25, this port being 1n communicationH with aT passage 42 which connects with an intake chamber 43 of the gear pump. From the exhaust chamber 44 of the gear pump, a passage 45 connects with an annular port 46 which surrounds one end of the valve member 30 andestablishes constant communication with the intake passage 36 in the valve member. The invention contemplates that the gear pump will provide Huid in yquantities greater than the output of the high pressureend of the pump and that a suitable'by pass will be provided for the excess fluid. This will insure that the cylinders will at all times be completely filled with fluid during the intake strokes of the pistons. In operation, the luidadmitted through the port 41 passes through the gear pump, which creates a pressure of approximately 3() pounds er square inch,'and from the exhaust cham er 44 of the gear pump the fluid passes throughthe connecting passages 45,

being' returned to the supply through a suitable by pass (not shown). ADurm the exhaust strokes of the istons the fluld will be forced out through t e ports 35 and 38 and the exhaust passages 39 and 40. Figs. 1 to A1t inclusive illustrate the yalve member in A detail and show the proper timing of the intake and exhaust ports for. the preferred form of the invention as disclosed herein.

From the fore oing it will be apparent that I have provided a pump of positive disg' placement such for example as is adapted for nuse in-"co'nnection with supplying hydraulic Huid for moving tool or work carriers in machine tools wherein it is desired to move the carrier at a uniform rate of speed irrespective of fluctuations in load on the carrier. When using an incompressible uid such results can readily be obtained. It will also be seen that I have provided means for varying the output of the pump from zero to a maximum determined by the capacity of the pump, this means being arranged to permit of an infinite number of steps intermediate maximum and minimum. Thus when so used in connection with the feeding of a tool or work support, the rate of such feed may be readilyv varied.

I claim as my invention:

1. A pump comprising, `in combination, a housing, a drive shaft rotatably mounted in said housing, a plurality of angularly displaced eccentrics on said shaft, a plurality of pivotally fulcrumed levers engaging said eccentrics, a cylinder block pivotally mounted on an axis parallel to said shaft, said cylinder rblock having inlet and outlet means, and a plurality of pistons mounted in said block arranged to be actuated by said `arms to discharge liquid through said outlet means.

2. In a pump comprising a cylinder block having a plurality of pistons slidably mounted in c linders, means for controllin the ilow of a uid toand from said cylin ers, and means for reciprocating said pistons including a drive shaft, a plurality'of angularly displaced eccentrics on said shaft, and means actuated by a-nd in continuous contact with said eccentrics having adjustable connections `with said pistons to permit the stroke of the pistons to be varied.

3. A pump comprising, in combination, a housing, a drive shaft rotatably mounted in saidhousing, a plurality of eccent'rics on said shaft, a pluiality of arcuately formed levers fulcrumed on an axis parallel to said shaft and having rollers on their free ends engageable by the eccentrics, a block having cylinders therein pivotally mounted on an axis parallel to said shaft having inlet and discharge ports formed therein for said cylinders, and a plurality of pistons slidably mounted in said -block and arranged to be i actuated by said levers.

4. A pump comprising, in combination, a

plurality of arcuately formed rotatably mounted shaft, a pluralit of angularly displaced eccentrics on-,sai shaft a levers fulcrumed on an axis parallel to said shaft and having their force arms engigeable' by said eccentrics, a cylinder block, aving inlet and discharge orts formed therein for the cylvinders, a p lllrality of pistons slidably mounted in saidblock arranged to be actuated by the load arms of said levers and means arranged to adjust`the effective length of one set of said arms whereby to vary the sti-oke `0f the pistons; Y fr .Y Y. .Y

5. A pump having, in combinatioma rotatabl mounted shaft, a cylinder having vinlet an discharge ports, .a -reciprocatory piston.

mounted in said cylinderfa pivotally fulcrumed lever having a load armof adj ustable length and a force arm of constant length arranged to actuate said piston, meanscarried on said shaft'arranged to operate the force arm of the lever and means to adjust the effective length of the load arm of said lever whereby 'to vary the vpiston stroke.

6. In a pump embodying@ cylinder. having intake and discharge ports and a piston in said cylinder arranged to deliver high pres-- sure fluid at a predetermined` volume per stroke, the combination, of a gear pump arranged to deliver fluid at a comparatively low pressure to said piston and a valve driven through said gear pump for controlling the inlet of low pressure fluid and the exhaust of high pressure fluid to and from said piston.

pump comprising, in combination, a

pivotally mounted cylinder, meansproviding intake and discharge ports for said cylinder, a piston in said cylinder, an arm-pivotally mounted on an axis parallel to the cylinder pivot and arranged to actuate said piston, and means for oscillatingsaid arm, pivotal movement of said cylinder being arranged to vary the stroke ofthe piston.

8. A pump comprising, in combination, a cylinder, a piston in thecylinder, means for supplying fiuid under pressure to the V`cylinder comprising a gear pump anda'control valve, said valve and one gear of said pump being mounted on the same shaft, and means to actuate the piston inthe opposite direction. y

9. A pump comprising,'incombinatiom a I a rotary valve for controlling said inlet and outlet openings, a gear pump for supplym liquid under lov:r pressure to said valve, sai gear pump having one of its gears mounted on and rotatable with said valve and the other one of its gears rotatably mounted in said housing, a shaft mounted in said housing, means operable by rotation of said shaft to actuate said pistons, and a pinion on said lo shaft in driving engagement with one 'of the gears of said pump so that said pump and said valve are operated by said shaft.

11. A pump comprising,in combination, a housing, a cylinder block having cylinders formed therein and mounted in said housing for pivotal movement about an axis perpendicular to said cylinders, said block having inlet and discharge ports for said cylinders, pistons in said cylinders, a plurality of arcuately formed levers pivoted at one end in said housing and each lever engaging one of said pistons, a shaft mounted in said housing having means engaging said levers to rock the same about their pivots, said cylinder block being tiltable about its pivotal axis to engage said pistons with diEerent points on said levers whereby to vary the stroke of the pistons, a valve for controlling said ports mounted in said block for rotation about the pivotal axis thereof, a.gear pump `having one gear mounted in the wall of said housing, and the other gear mounted on said valve for rotation therewith, one of said gears being driven from said shaft.

12. In a pump, in combination, a pivotally mounted block having a cylinder therein, a piston in said cylinder, means to conduct fluid to and from the cylinder, and means for actuating said piston comprising a pivotally mounted lever arcuate in form throughout a substantial portion of its length and arranged to engage the outer end of the piston, means for adjusting-the cylinder block about its pivot for varying the point of operative engagement of said piston with said lever and means for oscillating said lever. In testimony whereof, I have hereunto affixed my signature.

GUSTAF DAVID SUNDSTRAN D.

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